At my facility, and yours is probably similar: The purpose of call is to be available to the hospital. They are paying you because you are being "engaged to wait" in the event that an urgent/emergent case is booked and they need staff. You are technically still working while on call because there are requirements that you must adhere to while you are on-call such as: no drinking, no medications that will alter your mental capacity, no trips that could take you out of call-back distance and no events that mandate you to stay the entire duration without being able to leave for work duty.
There are people at my facility who live almost an hour a way from my hospital as well as people with very crappy reception even with signal boosters in their homes. They do two things: 1. Request a pager. This allows you two methods of communication and they can use either your phone or pager and increases your chances to be notified at the earliest possible convenience. 2. COMMUNICATE WITH THE OR FRONT DESK STAFF. I cannot stress this enough. Whoever runs the desk, notify them of your need for extra time to commute. Granted, try not to rely on this because it will not always be possible, but if the front desk staff knows youve spoken with them and need extra time, they will most likely pick up the phone and call you first because of your geographical location compared to your coworkers so you have more time. (Usually, they have a list of call staff and just go right down the line calling people. So they can make notes by your name to give you more heads up.) 3. Tell your boss everything. People appreciate honesty, and be pretty straightforward about it. In this field, it can be life or death as others have said, and they need to know you can be depended upon to take a patient at any time. If the boss is worth a crap, they will appreciate this forethought on your part. Express your concerns and just give a short run down about why. 4. Know all routes that lead to the hospital. Drive them every once in awhile so you know them like the back of your hand when you are in a rush. If you are rushing for time and need to be there immediately, don't forget to put your hazards on or you will get stopped and delay your OR. 5. Have scrubs and comfortable shoes in two places: your trunk (in case you can't return home) and beside your bed at night - so that if you're groggy and half asleep you wont be wasting time scrambling for this stuff. 6. Also, when they say 30-minute call back time, they mean commuting there, in the hospital, dressed in OR attire, behind the red line and ready to accept your patient to the OR room as Rose said. Not entirely commuting.
Being on-call is an extension of your job requirements. At my hospital, if you don't show up for call or if you are considerably late and someone has to cover for you, you can be written up or fired. Some hospitals are more lax than others, but it can impact your performance evaluations and your references at other hospitals that require you to take call. With that being said, there are people who will make remarks about call who may have more experience with it than you do, such as "two drinks is fine and I can sober up on the way there" or "I can make it, I probably wont get called anyway" or "it was quiet/calm when I left..." don't give in to their bad habits. The simple fact about this is if you are called-in its generally for something that cannot wait and if you're not at the top of your game someone could die. Take it seriously.